$\sin(270^{\circ}) = \text{?}$
Explanation: To find the sine using the unit circle, first find the angle. Drag the orange point around the circle until $270^{\circ}$ is selected. The correct angle is selected. Remember, the sine of an angle is represented by the $y$ coordinate of a point on the unit circle. The $y$ coordinate of the point is $-1$, so $\sin(270^{\circ}) = -1$.